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My part throttle gives part boost right now, which is nice. It used to climb steadily when in some mid-throttle position, kinda like creep, but different. I don't know if the GMBC fixed that or this combo setup. I did them within a couple of days.

But yeah, spool is quick. Lugging the motor still delivers a slow climb, which is related to the lack of PTFB situations, so I'll take it. Nailing it in 2nd or 3rd from about anywhere and it won't think twice before shoving me back in the seat. It's working well.

I set my low load sites on the boost map pretty high, then taper them back to reasonable numbers by the 60% column.

^^^is that a hallman product (the flexible cable and knob) or did you put that together yourself?

Basically, I'm looking for details on the drive setup, as far as parts go.

rex, after looking long and hard for alternate ideas, i just went ahead and got the hallman evo rx.

expensive? yes.

work exactly as promised? yes.

i had thought about using a speedometer drive cable to provide torque to any old ball/spring mbc, but the issue with those is that they are not really designed to be twisted both ways. i did not want rotational compliance making me guess how much i had actually turned the screw in the mbc. then of course you have the issue of mounting it, etc.

i know that hallman does make a retrofit kit for their mbcs so that they can be remote-ized. you could probably get one of those if you really like your current mbc. if not, i can heartily recommend their mbc. the rx has the ceramic ball, and it makes the tightest internal seal i've seen yet on ball and springs. by comparison the joe-p was a tinkertoy.

check and make sure you don't have the wrong nipples connected on the gmbcs.

at rest, with the car off, you should be able to blow from one connected nipple to the other. the car energizes the solenoid to raise boost. this will stop the flow through the solenoid.

when troubleshooting you can also disconnect the BCS entirely to make sure that your MBC plumbing is proper.

finally make sure that when you're WOT, whatever is controlling your solenoid goes to 100% duty. if you're using an oem ecu to do that, you need 100% wgdc and a boost target that's higher than you'll actually clamp it to with the MBC.

1) retain control over relatively low boost situations by springing your IWG only hard enough to hold the max boost you desire. right now my iwg spring is around 12psi and it'll hold >27psi (tested! )...

2) the EWG only opens up when the MBC does. the MBC controls max boost only. put a spring in it sized a few psi less than the minimum boost you want to VTA. in my case i'd put a 1-1.5 bar spring in.

3) since the 3-port solenoid is controlled by some electronic means, you can map desired boost to TPS and RPM. basically if you want max boost and EWG operation you send 100% duty to the 3-port. anything less will mean the IWG is open and limiting boost to some lower value. no issues with PTFB and boost control is retained at lower levels due to the relatively light spring in the IWG.

4) car is only wicked noisy when the EWG is open. when it's not, all turboback exhaust is in normal operation... ie, cats, mufflers, etc. who cares if it is restrictive and quiet, since:

5) when the EWG opens, you get the big VE benefit of a VTA dump. and it'll be noisy too!

the astute may notice that, on my car, this basically entails adding the EWG up pipe and actuator, removing a tee, and rerouting one pneumatic boost control hose to the new EWG.

You'll make a number of people happy with this idea, as it's been asked a number of times. Really, I think it's quite a trick idea, giving you streetability of a cutout, plus additional performance. I suppose this would also address boost creep issues, as those only happen at WOT, correct?

You'll make a number of people happy with this idea, as it's been asked a number of times. Really, I think it's quite a trick idea, giving you streetability of a cutout, plus additional performance.

yes.

quiet manners on the street, whenever you're not at max boost and the ewg is venting. very similar to the cutout-equipped car with a nice quiet axleback and a cat still in the pipe.

at wot you get BETTER VE gains than the cutout car since you are not only dumping to atmosphere, you're doing it from BEFORE the turbo hotside.

otoh, you would still give up SOME performance by having the turbine gasses pass through the "restrictive" turboback exhaust (that the cutout does not do), since the turbo shaft's energy is a function of mass flow rate and pressure differential across the turbine, and one would assume that there is some additional pressure seen at the turbine outlet. then again, all of the wastegate gasses are subtracted from that post turbo exhaust pipe, so that acts to reduce the pressure seen there. it's probably close to a toss-up.

Quote:

I suppose this would also address boost creep issues, as those only happen at WOT, correct?

the vta ewg def. takes care of that, whereas putting a cutout on a creeping car is going to make it worse.

Taking this one step further, if the internal wastegate is controlled by an interupt as per your diagram, couldn't you set the max duty at 100 with a target boost that was really high at 100% throttle? That should create the following scenario:

Target boost at 18psi and WGDC normal in 85% throttle column.
Target boost at 21 psi and WGDC at 100% in 86% throttle and up column.
MBC at 19psi.

Boost below 19 psi would be controlled by the internal wastegate only.
At above 85% throttle, the target boost will jump up and drive the WGDC to 100% closing the internal gate. Boost is now controlled by the external gate only.

I haven't tested this as I don't have an external gate yet, but the theory seems sound. You could set the crossover point for whatever boost and throttle % you want. Personally I would change the 100% throttle column to a value close to the crossover (like 86% above.) That way you would have a clear switchover point and then adjust it as needed for a smooth transition.

haha, exactly. I thought of using a stock STI Cat-back to keep the car quiet, and have one of those cut outs in the downpipe set at something like 15 psi. But I never thought of doing a EWG Dump to Atmosphere along with the cutout.

Taking this one step further, if the internal wastegate is controlled by an interupt as per your diagram, couldn't you set the max duty at 100 with a target boost that was really high at 100% throttle? That should create the following scenario:

Target boost at 18psi and WGDC normal in 85% throttle column.
Target boost at 21 psi and WGDC at 100% in 86% throttle and up column.
MBC at 19psi.

Boost below 19 psi would be controlled by the internal wastegate only.
At above 85% throttle, the target boost will jump up and drive the WGDC to 100% closing the internal gate. Boost is now controlled by the external gate only.

I haven't tested this as I don't have an external gate yet, but the theory seems sound. You could set the crossover point for whatever boost and throttle % you want. Personally I would change the 100% throttle column to a value close to the crossover (like 86% above.) That way you would have a clear switchover point and then adjust it as needed for a smooth transition.

very curious to see more about this. Not so much the ewg/iwg but the manual boost controller paired with a gm solenoid. I think having that slightly slow boost response is what I like least about my car. I know a manual boost controller would get me that quick spool but I like some of the safety features of the electronic boost control. Do you know of anyone that has set this up on an 04wrx? I know those didn't do so well with mbc's like the 02/03 wrx's did.

the real reason that 04+ WRX "did not like" MBC is the closed loop/ open delay programming by Subaru. Once that is tuned away (very simple) then there is no difference between using Ken's MBC/ BCS hybrid method.

That's what I thought the reason was for the 04+ not liking the manual boost controller but I wasn't too sure.
has anyone used a mbc with an ewg before? Would it actually work as well or not? I'm really curious to read this over and get a fully understanding of how ken's mbc/ebc works b/c right now I'm still a little confused.
So does the vacuum source hit the mbc first or the gm solenoid first?